I've got a new mini (2 gig ram, 2.0 Ghz, 256 vram) that I use as a HTPC and it works like a charm. I've wanted to add some gaming functionality. I've tried Quake Live so far and love it. Now I'm after:

Something in the RPG/Adventure genre: I've read reviews on NWN2, Fable:TLC and even Murder in the Abbey. But it's not quite what I'm looking for. Strong, emersive story is number 1 for me - I love the FF series for instance. Do you have something to recommend?

Arcade: Some classic arcade games for fun when friends come over, anything from pac man to street fighter variants, or silly space fighter games. You know the deal. Can stuff like this be had for free on some fansite or such?